767/757 RAT
 

Hey tech nerds,

it came up on the air India accident thread about possible RAT deployment. Someone said something along the lines of “every heavy Boeing twin has a RAT”, there was another post about a 757 that had a fuel control switch shut off SNAFU and they “flew all the way to wherever with the RAT deployed”.

And I’m like, whoa, I flew thousands of hours on the 767, around 30+ airframes and none of them had a RAT. So I asked chatGPT (ok I know could be incorrect), and it said the 767 200/300 didn’t have a RAT, but the 400 did. So I posted that (i didn’t say I asked chatGPT) and a couple of people were like “this dumbass flew the 767 and didn’t know it had a RAT”, “what an idiot”, “EVERY 767 Boeing built has a RAT” etc etc.

So, normally I don’t name companies but you’ll be able to guess - I flew 767-238ER PW and 767-338ER GE and 767-336ER (leased from BA).

All of those had backup HMGs, hydraulic generators, but no RAT! The 238ERs and 338ERs were 180 min ETOPS and, from memory, the -236ERs were maybe only 120 min ETOPS, I am a little fuzzy here but that may have been because they had one less HMG than our 338s. I think 338s had 3 HMGs and the 336s had only 2.

Our 238 and 338ERs flew across the pacific constantly. On non-revenue disposal (and I assume deliveries) they flew direct east coast Aus to west coast USA.

Have I gone senile? I feel like i am taking crazy pills!

Am I a “total dumbass” as “every 767 Boeing ever delivered had a RAT!”??

Any 767 drivers, what are/were the RAT configs on your aircraft? You don’t have to name your operator/company if you don’t want to, but identify if it’s a 200/300 or 400.

Both 757-200 (RB211-E4) and 767-300ER (CF6-80C2) experience, both had a RAT to power flight controls only from memory (although the 767 might have done a little more, I only flew it briefly so can't remember the detail). All the 767's had HMGs (again don't remember how many) but only some of the 757's had a single HMG, the rest were non-ETOPs and had none. 757's were all passenger config, the 767's were a mixture of factory built and converted freighters.

https://cimg9.ibsrv.net/gimg/pprune....6a0dd326f.jpeg
757-200 RAT location
https://cimg4.ibsrv.net/gimg/pprune....e065b7520.jpeg
767-300 RAT Location

A cursory search for images of Qantas 767s on a popular airliner photos site reveals a panel with a red outline in the same place as in the image Downwind posted, and a RAM AIR TURB switch on the cockpit overhead panel.

I don’t think the switch was enabled, I looked at a few photos, but they are angled and I couldn’t quite see… I don’t remember it being there. it wasn’t in our dual engine fail memory items that I recall (I assume it’s like the pax O2 switch in a depress where it’s pushed to backup the automatic activation if needed).

Theres no writing/red box near the right wing root below. Please show/link me the image of a red rat 767 with the red box if you can.

https://cimg4.ibsrv.net/gimg/pprune....bda3245bd.jpeg

Not here either.
https://cimg6.ibsrv.net/gimg/pprune....74f130c33.jpeg



Interestingly enough, the aircraft above, VH-OGV is now flying with the Israeli AF (jet went to maybe freighter stateside in the interim). The photo of that below clearly shows a red outline on that panel. I remember OGV because it was the only one of the entire fleet of 238/338s that had FADEC (did the RR 336s have FADEC?). OGV went to cairns for a few years before coming back in mainline colours.

I’m thinking the following.

1. I’m completely wrong. Every 238/338 767 had a RAT; or
2. The red rat, in their infinite Wisdom, got Boeing to disable the RAT. They have a history of annoying customer options. Israeli AF (or other operator in between) re-enabled it?
https://cimg1.ibsrv.net/gimg/pprune....fb3aac62d.jpeg

ideally we need a fellow ex 767-238/338 driver to come out of the woodwork and say option 1 or 2? :}

I would submit that as Boeing sells parts for the RAT on various 767 models, we can fairly infer that at least some 767s are fitted with them.
See https://shop.boeing.com/cpd/bpp_258t7100-7 and other items in the shop.

Re Dual Engine failure memory items, I have got a non Qantas QRH for the 767 and the RAT is turned on after the memory items.

Can’t be much help other than that I’m afraid!

752 for 25 years, some pax some pax to freighter conversions. Alongside that for 16 years 763, some brand new freighters some conversions. They all had a RAT. 75s we’re all RR, 76 all GE. Their only function was flying control hydraulics. Hth, rgds

yep, no doubt many have them, it appears most have a RAT. I don’t doubt that. There was a post of an FCOM page on the AI thread with a reference, I just wish I had old manuals to see what ours said.

Were the RATs possibly removed/deactivated and then reinstalled/reactivated at some point? It appears from these photos the panel is marked- on both OGx and ZXx series.

https://www.jetphotos.com/photo/6541888
https://www.jetphotos.com/photo/6751952
https://www.jetphotos.com/photo/6809138
https://www.jetphotos.com/photo/7105098
https://www.jetphotos.com/photo/7160608
https://www.jetphotos.com/photo/7751036
https://www.jetphotos.com/photo/7962488
https://www.jetphotos.com/photo/9113366

Gin, I was a Propulsion engineer at Boeing for 40 years - a good share of that working the 767. The RAT was basic on the 767 (and I believe the same for the 757, although no firsthand knowledge of that). It was required for cert to meet controllability requirements if both engines shutdown. Unlike the 737 (and 707/727), the 767 requires hydraulics for flight control, and windmilling engines simply don't provide sufficient hydraulic power to meet the minimum requirements. It's not optional, or removeable - it's required for cert. The HMGs were optional (added when ETOPS become the norm - ETOPS hadn't been invented at the time the 767 was originally certified), but the RAT was basic.
The 747 requires hydraulics for flight control, but (except for the 747-8), four windmilling engines would provide sufficient hydraulic power for controllability, so it didn't need a RAT.
It simply boggles my mind that you could have flown them and not known that.

copy, option 1 it is. The weight of evidence points towards “I am a senile dumbass”.

as for boggling the mind, I remember many tiny details about the 767 10ish years later, but zero about the RAT. That part of my brain must be mush.

Both those photos in post #5 and #6 (Qantas & Australian 767's) shows the red outline at the right aft wing root!

capn, I see a black outline on post 5 when I zoom in. No writing. The black outline, a smudge of hydraulic fluid and dust/grime, of the panel looks the same as every other panel or edge e.g. gear doors, pneumatic/pack? access panels.

But… see my previous post, I have conceded on other grounds (tdracer post). I will repeat for all your collective glee, “I am an idiot.”

https://cimg8.ibsrv.net/gimg/pprune....f77a48c4e.jpeg

We deployed, modded and tested many a RAT on the 767 fleet.

QF 200ERs had one HMG, whereas the rest (including VH-EAQ) had three fitted, from memory.

Noted. I have no memory of the system. I assume manual deploy was clear plastic flip guard over push switch like a gen drive disconnect or cargo fire bottle discharge? And with equally irreversible results?

MEA CULPA.

Yes, one time action from the Flt deck on P5.

Stow switch (and back drive handle for testing) is on the keel beam in the right wheel well.

We all have memories that play tricks on us sometimes. Don't beat yourself up about it. :O

Genuine question: never trained a dual engine failure in the sim ?

Apparently not 😂

For amusement purposes only, here's a previous ChatGPT question on the same subject:

https://cimg9.ibsrv.net/gimg/pprune....fc21e3bb4d.png

I read through a whole bunch of FCOMs a few months back and this basically fits my understanding. Everything civilian with powered flight controls and no manual reversion has a RAT, except the B741-744.

Even the A220, E-jets, Superjet, DC-10, and L1011.

What the RAT does to power flight controls varies (direct hydraulic, electric RAT with a hydraulic pump, dual hydraulic-electric) but it's always there.

Added the 'civilian' disclaimer because I think there's fighters where it's a bail-out event, and I'm not sure about the B-52 all-engines-out... C-5/C-17/A400M all have RATs.

The human mind is an extraordinary thing, in good and bad ways (the voice of a man who threw away a perfectly good banana yesterday and stood there holding the skin like a twerp). Don’t beat yourself up about it - particularly as dual engine failure stuff has only really had more prevalence/emphasis in the sim post Sully/Hudson.

Perhaps this would be helpful?

https://insanelygoodrecipes.com/banana-peel-recipes/

td...... I opened this topic with purpose but my reply needed to be directed to the smartest person on this topic. I am retired. Starting flying when I was 14 and just retired 4 years ago at 67. I flew for Eastern on the 727, A300 and DC-9. My younger brother , Capt B.P. Witcher was hired by United in 1985. The following is relative to my question. It involved my brother.Late on the evening of April 13, 2004, United Flight 854,

Boeing 767-300 service from Buenos Aires, Argentina, to

Miami, Fla., was in cruise flight at FL310 over the jungles

of southern Colombia, South America. Capt. Brian Witcher

and First Officers Donald Arlotta and Ross Windom were

the flight crew that night.

Brian and crew had a total electrical failure in flight. They landed in Bogota 42 minutes after the onset of the issue, most of that time on the main batteries only with intermittent AC/DC power. RAT did not deploy and presumably unavailable to them particularly once the issue was found afterwards by maintenance. Corrosion on a common bracket which grounds both AC/DC to the fuselage.

Were you aware of this event? I learned or was told that the RAT cannot be manually deployed and will not auto deploy if the generators have normal output, which they did in this case.

This was an ETOP aircraft.

Thanks

Billy Witcher

Do we need to distinguish? AFAIK the RAT on most Boeings, certainly the 767, drives a hydraulic pump to keep the control surfaces working in the event of main hydraulic failure. Would that have helped in the case of electrical failure?

(On some aircraft, not sure which, the RAT does drive a generator.)

B777….

To elaborate a bit on B2N2...
On the 757/767, the RAT is intended for a dual engine power loss - and only provides hydraulic power (and a limited amount of that). Even at max cruise altitude, if you lose both engines (and can't get them restarted), you're going to be on the ground in less than 30 minutes (rule of thumb - engine loss at cruise gets you ~100 miles and ~25 minutes endurance). The 757/767 has a backup battery good for 30 minutes - so (assuming a healthy battery), you'll be on the ground one way or another before the battery dies. The HMG (Hydro-Mechanical Generator) can provide sufficient electrical power to fly the aircraft if you lose all electrical generation, but at least one engine is still running (hence its need for ETOPS).

The 777 - being more electric and FBW - a 30 minute battery simply wasn't practical. So the RAT drives both a hydraulic pump and a generator to meet that 30 minutes after a dual engine power loss event.

I assume the 787 is the same as the 777, but no first-hand knowledge.

(Sniped by TDR...)

777 and 787 have both a hydraulic pump and an AC generator on the RAT shaft. RAT deploys for triple hydraulic failure or full AC loss.

757 and 767 have a hydraulic-only RAT.

There is then a (optional but probably present on ETOPS) DC hydraulically driven generator (HDG) that more-or-less just keeps the batteries topped up.

If the bleed air driven demand pump (ADP, assuming loss of electric pumps) is keeping the centre system pressurised, there is little point in deploying the RAT to also pressurise the system. The HDG will run happily off the ADP's flow.

This is not that dissimilar to the A330/A340 situation except their EMER GEN is AC output.

I might have to contact my manager. According to chatGPT, the aircraft i fly no longer has a RAT... That's at least two checklist items I need not worry about from now on. 😅